Fixed eruption

Probably results from an immunologically mediated inflammatory response to a given medication

Clinical manifestation

Develops 6-48 hours after administration of the causative drug; common etiologic agents: aspirin, barbiturates, co-trimoxa-zole, phenolphthalein, sulfonamides, and tetracycline; pruritus and burning, occasionally accompanied by fever; starts as a few sharply demarcated, erythematous macules that rapidly become erythematous plaques, usually on the lips, genitalia, and trunk; lesions heal hyperpigmentation; recurrence in the same site with readministration of the offending drug